A printing apparatus capable of printing desired information such as texts and images on a sheet-type printing medium, e.g., paper, film, and the like, is widely utilized as a data output apparatus in a word processor, a personal computer, a facsimile, and so forth.
Although various printing methods are available for such printing apparatus, recently an inkjet printing method has particularly attracted the attention because of its capability to perform non-contact printing on a printing medium such as paper, ease of color printing, and low noise. In general, a serial printing method is widely adopted because of its low cost and ease of downsizing. The configuration for the serial printing method includes a printing unit for reciprocally scanning a carriage incorporating a printhead discharging ink in accordance with desired printing data, and a conveyance unit for conveying a printing medium in a direction orthogonal to the scanning direction.
For improved printing speed, recently there are increasing numbers of printing apparatuses adopting the so-called bi-directional printing, in which printing is performed during the forward and backward scanning of the printing unit.
When printing, discharge timing should be corrected so that ink is discharged at the same position on a printing medium. For example, in a printing apparatus capable of bi-directional printing normally has a function for correcting ink discharge timing of the bi-directional printing so that ink is discharged at the same position on a printing medium in the forward and backward printing. By virtue of this correction function, excellent printing quality is ensured (refer to, e.g., Japanese Patent Application Laid-Open (KOKAI) No. 2001-129985). This document also discloses a typical correction method.
The ink discharge timing correction must mandatorily be performed before bi-directional printing. If the correction is not performed, intrinsic printing quality of the printer cannot be assured.
However, in reality, the printing apparatus is so constructed that printing is executable regardless of whether or not the ink discharge timing correction is performed for bi-directional printing.
There are some printer drivers which give a warning message to execute the ink discharge timing correction for bi-directional printing, when the printer driver is installed in an external host device. However, since installation of a printer driver is performed independently of the state of a printing apparatus, the warning message does not guarantee execution of the ink discharge timing correction.